In the design of steel building frames, various simplifying assumptions are usually introduced when determining member design forces. Typically, the beams are assumed to be either rigidly connected to the columns or simply supported. However, neither of these conditions is ever realized in actual frames. This paper describes the effects of connection flexibility on beam behavior; a parametric study is described for a family of 32 typical multistory frames representing several design philosophies. The study evaluates the adequacy of preliminary design methods for predicting both member forces and building drifts by comparing these parameters with those obtained from a linear elastic computer analysis which accounts for actual connection flexibility. Example results are shown indicating potential savings of steel from use of refined analytical methods.